With over 100 different histological subtypes, many rare brain and CNS tumor histologies cannot be adequately assessed for factors that may influence treatment or survival patterns. An estimated 1,000 ependymomas, 1,200 primary CNS lymphomas, 100 choroid plexus tumors, and 100 pineal parenchymal tumors are reported in the United States per year. Because of the small number of individuals who develop these tumors, studies are often restricted and may not provide information representative of the general population. The National Cancer Data Base (NCDB) is the largest clinical database in the world and collects information on all cancers, including all primary brain and CNS tumors, from Commission on Cancer accredited institutions, representing about 70% of all cancer cases diagnosed in the U.S. The NCDB collects a wealth of demographic, tumor characteristic, treatment, and follow-up (survival) data. The goal of this proposal is to describe presenting clinical characteristics and treatment and survival patterns for patients diagnosed with a subset of the rarest brain and CNS tumor subtypes, mainly ependymomas, primary CNS lymphomas, choroid plexus tumors, and pineal parenchymal tumors using data from the NCDB. A second goal of this proposal is to conduct a comprehensive evaluation of clinical or treatment factors that may influence survival time. We anticipate that approximately 7,000 ependymomas, 8,500 primary CNS lymphomas, 600 choroid plexus tumors, and 250 pineal parenchymal tumors will be available for analyses for the years 1998 - 2010, providing a large and diverse data set for analyses of these important tumors.